Posted: Tuesday, August 15, 2023
On August 14, Pfizer Inc. announced the U.S. Food and Drug Administration (FDA) has granted accelerated approval to elranatamab-bcmm (Elrexfio) for the treatment of adults with relapsed or refractory multiple myeloma who have received at least four prior lines of therapy (including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody). Elranatamab is an off-the-shelf, fixed-dose, subcutaneously administered B-cell maturation antigen (BCMA)–CD3-directed bispecific antibody. Approval was based on the results of the single-arm phase II MagnetisMM-3 trial, and continued approval for this indication is contingent upon verification of clinical benefit in a confirmatory trial(s).
Data from cohort A (n = 123) of the MagnetisMM-3 study showed responses among heavily pretreated patients with relapsed or refractory multiple myeloma who received elranatamab as their first BCMA-directed therapy. Among the patients in this study who received four or more lines of therapy prior to elranatamab (n = 97), the overall response rate was 58%, with an estimated 82% maintaining the response for at least 9 months. The median time to first response was 1.2 months.
In longer-term efficacy data for cohort A, presented at the European Hematology Association 2023 Hybrid Congress, the objective response rate was 61%, and the median duration of response, overall survival, and progression-free survival had not yet been reached at 14.7 months of median follow-up. Among the 50 responding patients who switched to every-other-week dosing at least 6 months prior to the data cutoff date, 80% maintained or improved their response after the switch.
The label for elranatamab contains a boxed warning for cytokine-release syndrome and neurologic toxicity (including immune effector cell–associated neurotoxicity syndrome), in addition to warnings and precautions for infections, neutropenia, hepatotoxicity, and embryofetal toxicity. The most common adverse reactions (incidence ≥ 20%) are cytokine-release syndrome, fatigue, injection-site reaction, diarrhea, upper respiratory tract infection, musculoskeletal pain, pneumonia, decreased appetite, rash, cough, nausea, and fever (pyrexia). Given the risk of these toxicities, elranatamab is available only through a restricted program called the ELREXFIO Risk Evaluation and Mitigation Strategy.
For more information on elranatamab, view the full prescribing information.